SIST EN ISO 307:2007
(Main)Plastics - Polyamides - Determination of viscosity number (ISO 307:2007)
Plastics - Polyamides - Determination of viscosity number (ISO 307:2007)
This International Standard specifies a method for the determination of the viscosity number of dilute solutions of polyamides in certain specified solvents. Polyamide samples must be completely soluble in the solvents mentioned. Additives such as flame-retardants and modifiers often interfere with the viscosity measurement, having an increasing effect on the viscosity number in formic acid and a decreasing effect on the viscosity number in sulfuric acid. The extent of the effect for polyamide compounds depends on the additive, the quantity of the additive, the presence of other additives and the compounding conditions. For pure polyamides or polyamides containing additives that do not interfere with the viscosity measurement, the determination of the viscosity number of a polyamide provides a measure of the molecular mass of the polymer. The viscosity number of pure polyamides or polyamides which contain additives that do not interfere with the viscosity measurement can be converted from one solvent to another. The viscosity number of polyamides containing additives that do interfere with the viscosity measurement is specific to the solvent used and the material composition. In this case, the measured viscosity number cannot be converted from one solvent to another. The method is applicable to the polyamides designated PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 and PA MXD6 as defined in ISO 1874-1, as well as to copolyamides, compounds of polyamides and other polyamides that are soluble in one of the specified solvents under the specified conditions. The method is not applicable to polyamides produced by anionic polymerization of lactams or produced with cross-linking agents; such polyamides are normally insoluble in the specified solvents. The viscosity number is determined by the general procedure specified in ISO 1628-1, observing the particular conditions specified in this International Standard.
Kunststoffe - Polyamide - Bestimmung der Viskositätszahl (ISO 307:2007)
Diese Internationale Norm legt ein Verfahren zur Bestimmung der Viskositätszahl von verdünnten Polyamid¬lösungen in bestimmten, festgelegten Lösemitteln fest.
Die Polyamidproben müssen in den aufgeführten Lösemitteln vollständig löslich sein. Zusatzstoffe, wie z. B. Flammschutzmittel und Modifikatoren, wirken sich oft störend auf die Viskositätsmessung aus, wobei sie in Ameisensäure zu einem größeren und in Schwefelsäure zu einem kleineren Wert der Viskositätszahl führen. Der Grad der Auswirkung hängt bei Polyamid Compounds von dem Zusatzstoff, der Menge an Zusatzstoff, dem Vorliegen weiterer Zusatzstoffe und den Compoundierbedingungen (Aufbereitungsbedingungen) ab.
Bei reinen Polyamiden oder von Polyamiden mit Zusatzstoffen, die die Viskositätsmessung nicht stören, ergibt die Bestimmung der Viskositätszahl eines Polyamids ein Maß für die Molekülmasse des Polymers. Die Viskositätszahl von reinen Polyamiden oder von Polyamiden mit Zusatzstoffen, die die Viskositätsmessung nicht stören, kann von einem Lösemittel auf ein anderes umgewandelt werden.
Die Viskositätszahl von Polyamiden mit Zusatzstoffen, die sich störend auf die Viskositätsmessung auswirken, ist spezifisch für das verwendete Lösemittel und die Werkstoffzusammensetzung. In diesem Fall kann die gemessene Viskositätszahl nicht von einem Lösemittel auf ein anderes umgewandelt werden.
Das Verfahren ist auf Polyamide mit den Bezeichnungen PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 und PA MXD6, wie in ISO 1847 1 definiert, und Copolyamide, Polyamid Compounds und sonstige Polyamide anwendbar, die unter den festgelegten Bedingungen in einem der festgelegten Lösemittel löslich sind.
Plastiques - Polyamides - Détermination de l'indice de viscosité (ISO 307:2007)
L'ISO 307:2007 spécifie une méthode pour la détermination de l'indice de viscosité de solutions diluées de polyamides dans certains solvants spécifiés.
Pour les polyamides purs ou les polyamides contenant des additifs qui n'affectent pas le mesurage de la viscosité, la détermination de l'indice de viscosité d'un polyamide fournit une mesure de la masse moléculaire du polymère. L'indice de viscosité des polyamides purs ou des polyamides qui contiennent des additifs qui n'affectent pas le mesurage de la viscosité peut être converti d'un solvant à un autre.
L'indice de viscosité des polyamides contenant des additifs qui affectent le mesurage de la viscosité est spécifique au solvant utilisé et à la composition du matériau. Dans ce cas, l'indice de viscosité mesuré ne peut pas être converti d'un solvant à l'autre.
La méthode est applicable aux polyamides désignés PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 et PA MXD6, ainsi qu'aux copolyamides, aux composés polyamides et aux autres polyamides solubles dans l'un des solvants spécifiés dans les conditions spécifiées.
La méthode n'est pas applicable aux polyamides obtenus par polymérisation anionique des lactames ou produits avec des agents de réticulation; de tels polyamides étant normalement insolubles dans les solvants spécifiés.
Polimerni materiali - Poliamidi - Določanje števila viskoznosti (ISO 307:2007)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 307:2007
01-september-2007
1DGRPHãþD
SIST EN ISO 307:2003
3ROLPHUQLPDWHULDOL3ROLDPLGL'RORþDQMHãWHYLODYLVNR]QRVWL ,62
Plastics - Polyamides - Determination of viscosity number (ISO 307:2007)
Kunststoffe - Polyamide - Bestimmung der Viskositätszahl (ISO 307:2007)
Plastiques - Polyamides - Détermination de l'indice de viscosité (ISO 307:2007)
Ta slovenski standard je istoveten z: EN ISO 307:2007
ICS:
83.080.20 Plastomeri Thermoplastic materials
SIST EN ISO 307:2007 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD
EN ISO 307
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2007
ICS 83.080.20 Supersedes EN ISO 307:2003
English Version
Plastics - Polyamides - Determination of viscosity number (ISO
307:2007)
Plastiques - Polyamides - Détermination de l'indice de Kunststoffe - Polyamide - Bestimmung der Viskositätszahl
viscosité (ISO 307:2007) (ISO 307:2007)
This European Standard was approved by CEN on 14 May 2007.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 307:2007: E
worldwide for CEN national Members.
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EN ISO 307:2007 (E)
Foreword
This document (EN ISO 307:2007) has been prepared by Technical Committee ISO/TC 61
"Plastics" in collaboration with Technical Committee CEN/TC 249 "Plastics", the secretariat of
which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by November 2007, and conflicting national
standards shall be withdrawn at the latest by November 2007.
This document supersedes EN ISO 307:2003.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United
Kingdom.
Endorsement notice
The text of ISO 307:2007 has been approved by CEN as EN ISO 307:2007 without any
modifications.
2
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INTERNATIONAL ISO
STANDARD 307
Fifth edition
2007-05-15
Plastics — Polyamides — Determination
of viscosity number
Plastiques — Polyamides — Détermination de l'indice de viscosité
Reference number
ISO 307:2007(E)
©
ISO 2007
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ISO 307:2007(E)
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ii © ISO 2007 – All rights reserved
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ISO 307:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Principle. 3
5 Reagents and materials . 3
5.1 Solvents and reagents. 3
5.2 Cleaning liquids . 4
6 Apparatus . 4
7 Preparation of test samples. 5
7.1 General. 5
7.2 Samples containing less than 98 % (by mass) polyamide . 5
8 Calculation of test portion . 6
9 Selection of solvent. 6
10 Procedure . 7
10.1 Cleaning of the viscometer. 7
10.2 Preparation of test solution . 7
10.3 Measurement of flow times. 9
11 Expression of results . 10
12 Repeatability and reproducibility. 10
13 Relationship between the viscosity number determined in 96 % (by mass) sulfuric acid
solution and the viscosity determined in various solvents . 11
14 Test report . 11
Annex A (informative) Determination of the concentration of commercial sulfuric acid (95 % to
98 %) and adjustment to 96 % by titration .13
Annex B (informative) Determination of the concentration of sulfuric acid (95 % to 98 %) and
adjustment to 96 % by flow time measurement in a small capillary viscometer . 16
Annex C (informative) Determination of the concentration of commercial formic acid and
adjustment to 90 % by titration . 18
Annex D (informative) Determination of the concentration of commercial formic acid and
adjustment to 90 % by density measurement. 20
Annex E (informative) Relationship between the viscosity number determined in 96 % (by mass)
sulfuric acid solution and the viscosity determined in various solvents. 23
Bibliography . 33
© ISO 2007 – All rights reserved iii
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ISO 307:2007(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 307 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9, Thermoplastic
materials.
This fifth edition cancels and replaces the fourth edition (ISO 307:2003), which has been technically revised.
iv © ISO 2007 – All rights reserved
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ISO 307:2007(E)
Introduction
This International Standard specifies a method for the determination of the viscosity number of dilute solutions
of polyamides in certain specified solvents. The determination of the viscosity number of a polyamide provides
a value that depends on the molecular mass of the polymer, but does not strictly correlate with the molecular
mass.
Additives such as flame-retardants and modifiers often interfere with the viscosity measurement and may
have an increasing effect on the viscosity number in one solvent and a decreasing effect in another solvent.
The extent of the effect depends among others on the additive, the quantity of the additive, the presence of
other additives and reactions.
The viscosity number of a polyamide sample containing additives that interfere with the viscosity
measurement, measured in a specific solvent, represents a specific viscosity number for the polyamide under
investigation and the actual measurement conditions. The measured viscosity number cannot, in principle, be
converted from one solvent to another and is only suitable for intra-product comparison.
The viscosity number of pure polyamides or polyamides containing additives that do not interfere with the
viscosity measurement can be converted from one solvent to another by a general relationship for that type of
polyamide.
Polyamide test samples for the determination of the viscosity number must be completely soluble in the
solvents mentioned. Additives contained in them, like glass and carbon fibres, must be separated from the
solution.
As it is not possible to distinguish between extractables such as caprolactam, its oligomers and other
extractable additives, these are considered as an essential part of the sample and therefore included in the
sample mass.
The test method is applicable for production control and intra-product comparison even if the polyamide
contains additives that do interfere with the viscosity measurement. However, it should be realised that
deviations of the viscosity number can be caused by either the polyamide itself, effects caused by the
additives present, or a combination of these.
The interference of additives with the viscosity determination can be checked by comparing the viscosity
results of dry blend mixtures and regular production samples at several concentrations of the additive under
investigation and in the solvents concerned. It should be noted that the other additives present also could
influence the viscosity result.
The repeatability and reproducibility of the test method are strongly influenced by the correctness of the
solvent concentration, the use of the Hagenbach correction if applicable and the temperature of the solvent on
diluting the sample solution.
In this International Standard two specific viscometers are recommended. Furthermore, other types of
viscometers listed in ISO 3105 may also be used, provided that the results are demonstrated to be equivalent
to those measured with the recommended viscometers. It is to be expected that in the next revision the use of
the other types of viscometers will be excluded.
© ISO 2007 – All rights reserved v
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INTERNATIONAL STANDARD ISO 307:2007(E)
Plastics — Polyamides — Determination of viscosity number
1 Scope
This International Standard specifies a method for the determination of the viscosity number of dilute solutions
of polyamides in certain specified solvents.
Polyamide samples must be completely soluble in the solvents mentioned. Additives such as flame-retardants
and modifiers often interfere with the viscosity measurement, having an increasing effect on the viscosity
number in formic acid and a decreasing effect on the viscosity number in sulfuric acid. The extent of the effect
for polyamide compounds depends on the additive, the quantity of the additive, the presence of other
additives and the compounding conditions.
For pure polyamides or polyamides containing additives that do not interfere with the viscosity measurement,
the determination of the viscosity number of a polyamide provides a measure of the molecular mass of the
polymer. The viscosity number of pure polyamides or polyamides which contain additives that do not interfere
with the viscosity measurement can be converted from one solvent to another.
The viscosity number of polyamides containing additives that do interfere with the viscosity measurement is
specific to the solvent used and the material composition. In this case, the measured viscosity number cannot
be converted from one solvent to another.
The method is applicable to the polyamides designated PA 46, PA 6, PA 66, PA 69, PA 610, PA 612, PA 11,
PA 12, PA 6T/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66 and PA MXD6 as defined in ISO 1874-1, as
well as to copolyamides, compounds of polyamides and other polyamides that are soluble in one of the
specified solvents under the specified conditions.
The method is not applicable to polyamides produced by anionic polymerization of lactams or produced with
cross-linking agents; such polyamides are normally insoluble in the specified solvents.
The viscosity number is determined by the general procedure specified in ISO 1628-1, observing the particular
conditions specified in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 1628-1, Plastics — Determination of the viscosity of polymers in dilute solution using capillary
viscometers — Part 1: General principles
ISO 1874-1, Plastics — Polyamide (PA) moulding and extrusion materials — Part 1: Designation
ISO 3105, Glass capillary kinematic viscometers — Specifications and operating instructions
ISO 3451-4, Plastics — Determination of ash — Part 4: Polyamides
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ISO 307:2007(E)
ISO 15512, Plastics — Determination of water content
ASTM D789, Standard test methods for determination of relative viscosity of polyamide (PA)
JIS K 6920-2:2000, Plastics — Polyamide (PA) moulding and extrusion materials — Part 2: Preparation of test
specimens and determination of properties
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1628-1 and the following apply.
3.1
viscosity number of a polymer
number calculated by the following formula for the viscometers mentioned in this International Standard and
flow times long enough so that no kinetic energy correction need be applied:
⎛⎞
η 1
VN=−1× (1)
⎜⎟
η c
⎝⎠0
where
2
η is the viscosity of a solution of the polymer in a specified solvent, in Pascal seconds or N/m⋅s;
η is the viscosity of the solvent, expressed in the same units as η;
0
η
is the relative viscosity of a solution of the polymer in a specified solvent;
η
0
c is the concentration, in grams per millilitre, of the polymer in the solution;
VN is the viscosity number, expressed in millilitres per gram.
NOTE 1 For a particular viscometer used and with substantially equal densities of the solvent and solution, the
viscosity ratio is given by the flow time ratio for the solution concentration:
η
(2)
η
0
where
η
is the relative viscosity of a solution of the polymer in a specified solvent.
η
0
NOTE 2 As mentioned in ISO 3105, in case of flow times below 200 s and 60 s, for type 1 and type 2 Ubbelohde
viscometers respectively, a correction for kinetic correction has to be applied: the so-called Hagenbach correction. For
other types of viscometers, the kinetic energy correction has to be applied if the correction is W 0,15 %.
NOTE 3 The flow time of a liquid is related to its viscosity by the formula
η ⎛⎞A
vC==×t− (3)
⎜⎟
2
ρ
t
⎝⎠
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ISO 307:2007(E)
where
v is the viscosity/density ratio, in metres squared per second;
ρ is the density of the liquid, in kilograms per cubic metre;
C is the constant of the viscometer, in metres squared per second squared;
t is the flow time, in seconds;
A is the parameter of the kinetic correction in metres squared seconds.
NOTE 3 For a particular viscometer used, with substantially equal densities of the solvent and solution and a given
kinetic factor, the viscosity ratio
η
(4)
η
0
is given by the flow time ratio for the solution concentration in this International Standard, each flow time reduced with the
so-called Hagenbach correction (in seconds) given by the manufacturer for the viscometer as a function of the flow time.
4 Principle
The times of flow of a solvent and a solution of the polyamide at a concentration of 0,005 g/ml in the solvent
are measured at 25 °C, the same viscometer being used for both measurements. The viscosity number is
calculated from these measurements and from the known concentration of the solution.
5 Reagents and materials
5.1 Solvents and reagents
Only reagents of recognised analytical grade and only distilled water or water of equivalent purity shall be
used.
WARNING — Some chemicals, for example 1,1,2,2-tetrachloroethane, are prohibited in some countries.
The user shall check on the national regulations before applying the chemicals mentioned in this
standard.
Avoid contact with the skin and inhalation of any vapours of the solvents and cleaning liquids.
5.1.1 Sulfuric acid, 96,00 % ± 0,20 % (by mass) solution.
For the determination of the concentration of commercial sulfuric acid (95 % to 98 %) and adjustment to
96,00 %, see Annexes A and B.
5.1.2 Formic acid, 90,00 % ± 0,15 % (by mass) solution.
The solvent shall be stored in a brown glass bottle. Its concentration shall be checked at least every 2 weeks.
It shall not contain more than 0,2 % acetic acid or methyl formate.
For the determination of the concentration of commercial formic acid (90 %) and adjustment to
90,00 % ± 0,15 %, see Annexes C and D.
5.1.3 m-Cresol, meeting the following specifications:
⎯ appearance: clear and colourless
⎯ m-cresol content: 99 % (by mass) min.
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ISO 307:2007(E)
⎯ o-cresol content: 0,3 % (by mass) max.
⎯ water content: 0,13 % (by mass) max.
m-Cresol of the required purity can be obtained by distillation of chemically pure m-cresol, preferably in
vacuum.
To avoid oxidation, nitrogen shall be used for pressure compensation. Its purity may be checked by gas
chromatography. The solvent shall be stored in a brown glass bottle.
5.1.4 Phenol, 99 % (by mass) min.
5.1.5 1,1,2,2-tetrachloroethane, 99,5 % (by mass) min.
5.1.6 Phenol/1,1,2,2-tetrachloroethane.
Weigh out 6 parts by mass of phenol (5.1.4) and dissolve in 4 parts by mass of 1,1,2,2-tetrachloroethane
(5.1.5). Work to an accuracy of 1 % or better in the weighings. Stir the mixture in its original container at 23 °C
to prevent crystallization.
5.1.7 Orthophosphoric acid, 85 % (by mass), density 1,71 g/l.
5.1.8 m-Cresol/phosphoric acid.
Transfer 50 ml of m-Cresol (5.1.3) into a weighing flask (6.4) and add with a glass pipette (6.5) 0,14 ml of
orthophosphoric acid (5.1.7). Close the flask and stir with a magnetic stirrer for 30 min at 100 °C. Add the
solution to approximately 800 ml of m-cresol in a volumetric flask while continuously stirring. Rinse the
weighing flask several times with m-cresol and add this to the m-cresol solution. Remove the magnetic stirrer
and dilute to the mark. Stir the solution for 30 min.
5.2 Cleaning liquids
5.2.1 Chromic acid solution, prepared by mixing equal volumes of sulfuric acid (96 %, ρ = 1,84 g/ml,
0
industrial quality) and a saturated solution of potassium dichromate (99,5 %, industrial quality). If required, the
chromic acid solution may be replaced by other equally effective cleaning liquids.
5.2.2 Acetone (99,5 %, industrial quality), or any water-soluble low-boiling-point solvent (industrial quality).
6 Apparatus
6.1 Vacuum drying cabinet, with pressure less than 100 kPa.
6.2 Balance, accurate to 0,1 mg.
6.3 Volumetric flask, of capacity 50 ml or 100 ml, complying with the requirements of ISO 1042, fitted with
a ground-glass stopper.
6.4 Weighing flask, 100 ml, fitted with a ground-glass stopper.
6.5 Pipette, 0,2 ml, readable to 0,01 ml.
6.6 Shaking apparatus or magnetic stirrer.
6.7 Sintered-glass filter, with a pore size between 40 µm and 100 µm (grade P 100), or stainless-steel
2
sieve, with apertures of about 0,075 mm .
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ISO 307:2007(E)
6.8 Viscometer, of the suspended-level Ubbelohde type, complying with the requirements of ISO 3105.
The essential dimensions of the viscometer are shown in Figure 1. For use with the formic acid solution (5.1.2),
the inside diameter of the capillary shall be 0,58 mm ± 2 % (complying with the requirements of size No. 1 of
ISO 3105). For use with the sulfuric acid solution (5.1.1) or m-cresol (5.1.3), the inside diameter of the
capillary shall be 1,03 mm ± 2 % (complying with the requirements of size No. 2 of ISO 3105).
Other types of viscometer listed in ISO 3105 may be used, provided that the results are demonstrated to be
equivalent to those of the Ubbelohde viscometers specified above. In cases of dispute, the recommended
viscometer shall be used.
ISO 1628-1 shall be followed on selecting other type(s) of viscometer.
NOTE In this International Standard, the No. 1 and No. 2 Ubbelohde viscometers according to ISO 3105 are
recommended. It is to be expected that at the next 5 year revision only these two viscometers will be allowed.
6.9 Thermometer, a liquid-in-glass, “total immersion” thermometer, reading to 0,05 °C in the range to be
used and in a known state of calibration, is suitable. Other thermometric devices of at least equal precision
may be used.
6.10 Thermostatic bath, capable of being maintained and controlled at 25,00 °C ± 0,05 °C.
6.11 Time device, for example a stop-watch, accurate to 0,1 s.
6.12 Centrifuge.
7 Preparation of test samples
7.1 General
Polyamide test samples for the determination of the viscosity number shall be soluble in the solvents
mentioned, except for additives present, such as reinforcement-fillers.
NOTE The dissolution time of some samples may be too long for adequate production control. In these cases the
material may be ground in order to shorten the dissolution time, provided that the results are demonstrated to be
equivalent.
7.2 Samples containing less than 98 % (by mass) polyamide
For samples containing more than 2 % additives, the amount of additives shall be either determined by a
specifically developed method or taken from the recipe. The method of determination will be mentioned in the
report.
The water content of the sample shall be determined according to ISO 15512. The ash content shall be
determined according to ISO 3451-4.
The correct amount of polyamide sample to be weighed out is calculated using the equation in Clause 8.
Some additives, e.g. antimony trioxide and zinc sulfide, are completely volatilized during the calcination
according ISO 3451-4. Materials reinforced with glass fibre contain flame-retardant antimony trioxide and/or other
volatilizable additives. If the total content of additives is more than 2 %, these shall be brought into account by
the formulation of the sample for calculating the exact test portion.
NOTE For production quality control purposes, the laboratory response time for determination of the additives may
be too long for adequate production control. In these cases the additive(s) content in the production recipe can be used for
calculating the amount of sample, if the total variation of the polymer content is less than 4 % (by mass), e.g. 65 % PA
would range from 63 % to 67 %.
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ISO 307:2007(E)
8 Calculation of test portion
Calculate the mass m , in milligrams, of the test portion according to Equation (5):
c
250
m = (5)
c
ww++w
12 3
1−
100
where
w is the water content of the sample, expressed as a percentage by mass, determined in accordance
1
with ISO 15512;
w is the content of inorganic materials (for example fillers or glass fibres) in the sample, expressed as a
2
percentage by mass, determined in accordance with ISO 3451-4;
w is the content of other materials (for example other polymers, such as polyolefins, or additives, such
3
as flame-retardants), expressed as a percentage by mass, determined by appropriate methods.
For the content of the additive(s) which cannot be determined, the content according to the product recipe
shall be used.
9 Selection of solvent
The value of the viscosity number of a polyamide depends on the solvent used.
The solvent or solvents to be used for a particular polyamide are specified below.
a) For PA 6, PA 46, PA 66, PA 69, PA 610, PA MXD6 and corresponding copolyamides, formic acid solution
or sulfuric acid shall be used as solvent. For polyamides containing additives that liberate gases in acidic
solvents, m-cresol shall be used as the solvent. In cases of dispute, formic acid shall be used as a solvent.
b) For PA 612, the sulfuric acid solution or m-cresol shall be used as solvent. In cases of dispute, m-cresol
shall be used.
c) For PA 11, PA 12, PA 11/12 copolymers, m-cresol shall be used as a solvent. In cases of dispute about
ammonium carboxylate influencing v
...
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